1. Field of the Invention
The present invention is generally related to a boat which has channels formed in the rearward portion of its hull and, more particularly, to a boat which is particularly shaped to facilitate the use of a propulsor in such a way that the boat is able to achieve a more optimum planning angle and also to improve the handling characteristics of the boat.
2. Description of the Prior Art
U.S. Pat. No. 3,600,733, which issued to Lippisch on Aug. 24, 1971, describes a planing boat hull. The hull is designed for maintaining a substantially constant trim angle throughout a slow to moderate speed range, with the hull having a flat-bottom central longitudinal tunnel with its side walls tapering outwardly from bow to stem to gradually increase the tunnel width, and a central lifting surface extending longitudinally throughout the tunnel, with the lifting surface being inclined to the tunnel bottom to form a channel extending forwardly of the medial portion thereof and forming an inclined plane projecting downwardly from the tunnel bottom and extending rearwardly of the medial portion.
U.S. Pat. No. 4,713,028, which issued to Duff on Dec. 15, 1987, describes a shallow water boat design. The boat provides full operation even in shallow water utilizing an outboard motor. The boat includes a main hull, a displaceable transom to which the motor is mounted and a displaceable hull section. The displaceable transom is received in sliding engagement within two guide brackets mounted to the main hull. The displaceable hull section is connected to the displaceable transom by a hinge along a rear edge. The leading edge of the displaceable hull section is received and rests within a lip in the main hull. Actuator cylinders mounted in alignment with the guide brackets raise and lower the transom and the rear end of the displaceable hull section while the leading edge of the displaceable hull section pivots and slides in the lip. When the motor is raised for shallow water operation the displaceable hull section forms a flow channel for directing water to the propeller and intake port of the motor so as to prevent damage and provide proper and efficient water cooling.
U.S. Pat. No. 5,570,649, which issued to Austin on Nov. 5, 1996, describes a boat hull structure comprising a pair of laterally spaced hulls having V-shaped bottom portions that are each symmetrical about a vertical plane extending through its longitudinal axis. A channel defined in each bottom portion that extends substantially along the length of each hull for trapping air and water to provide lift and to reduce certain disadvantageous performance is disclosed. Each channel is defined by a pair of spaced, parallel and vertical channel walls and a horizontal base that interconnects the channel walls. A pair of strikes defined on each bottom portion that straddles the channel to define a high speed planing surface is described. The strikes preferably are located at the same elevation as the base of the channel so that the boat can plane on the strikes and the base of the channel at the same time. With this construction, the planing surface area of the boat hull structure is reduced, which enhances the speed performance of the boat hull structure.
U.S. Pat. No. 5,205,765, which issued to Holden on Apr. 27, 1993, describes a boat hull and propulsion system. A device, such as a boat hull and propulsion system, is described for effecting relative movement of a flowable substance, such as water. A channel having open upstream and downstream ends at least partially defines a flow path. The channel includes a fully laterally closed core section distal the upstream end with a fluid moving rotor rotatably mounted therein and a transition section extending forward from the upstream end of the core section. The channel configuration and rotor are adapted to permit a continual decrease in the transverse cross-sectional area of the flow path downstream along the transition section. If the device is a boat hull, the bow is configured to cause gas lubrication thereof by interaction with the water in motion. The transition sections of the channels may be open bottomed and ribs are provided to house driveshafts extending downwardly to the rotors. The bow provides lift, and downwardly facing surfaces adjacent the stem are inclined to balance this lift, so that the boat can rise on the water with an upward translating type movement. The rotors themselves are also improved.
U.S. Pat. No. 5,111,767, which issued to Haines on May 12, 1992, describes a boat hull having an underside, a transom and a recess adjacent the transom extending at partially a transverse dimension or width of the underside. There is also provided a transverse step defining a transverse boundary of the recess as well as an internal hollow venting body or reservoir having at least a pair of access ports of restrictive cross sectional size compared with the enlarged cross sectional area of the venting body. The venting body is in fluid communication with the recess and the hull exterior wherein during travel of the boat hull venting of a low pressure area adjacent the recess can take place without water gaining access to the hull interior in the event of hard turning or reversing, the water being trapped in the hollow venting body or reservoir. Preferably, the venting body is elongate having a major dimension corresponding to the enlarged cross sectional area which defines a longitudinal extent of the venting body and a minor dimension defining a transverse extent of the venting body.
U.S. Pat. No. 4,903,626, which issued to Haines on Feb. 27, 1990, describes a planing motor boat hull. The hull includes a bow, a transom, a keel and an underside having a transverse step adjacent the transom which extends partially the width of the underside and a recess bounded by the transverse stop and a pair of side walls and having an open transom end. The hull underside may further include a pair of substantially planar portions wherein each portion is located adjacent to a respective side wall of the recess. The hull underside may further include a plurality of lift strakes including an outermost lift strake terminating at or adjacent the transom, one or more intermediate lift strakes terminating short of the transom and the outermost lift strake and an innermost lift strake located adjacent to the keel terminating short of the transom ends of the one or more intermediate lift strakes.
U.S. Pat. No. 4,392,448, which issued to Shirley on Jul. 12, 1983, describes a ski boat. The ski boat is intended for producing a relatively small, well-defined wake and a relatively smooth working table. It includes a V-shaped keel section. The angle of the xe2x80x9cVxe2x80x9d increases towards the stern of the hull. A chine panel is mounted at each of the outboard edges of the keel section. A secondary chine is locate on each side of the keel section, being parallel to the centerline of the V-shaped keel section and following the contour of the keel section. A concave depression panel is located at the stern of the boat, extending forwardly therefrom into the keel section.
U.S. Pat. No. 5,570,650, which issued to Harley on Nov. 5, 1996, describes a surface effect vessel hull. The surface effect hull is particularly suitable for use with a catamaran vessel. The twin hulls each comprise a V-shaped portion and a recess portion that receives pressurized gas therein. The V-shaped bow portion creates dynamic lift and the pressurized air portion creates an air cushion for reduction of drag.
U.S. Ser. No. 09/871,098 which was filed by Chrunyk on Dec. 20, 2001, describes a method of controlling the attitude of a boat at high speed through boat hull design and a boat hull. The method involves a first step of forming a pair of high speed steps in the hull of the boat. The pair of high speed steps provides enough surface area to control ride attitude, while reducing the wetted area of the hull to decrease drag. A second step involves forming transition steps to provide a transition to the high speed steps as the boat accelerates. In addition to reducing drag, the method aids in turning and lifting of the hull by trapping air and water in the steps.
U.S. Pat. No. 6,138,601, which issued to Anderson et al on Oct. 31, 2000, discloses a boat hull with a configurable planing surface. A V-bottom planing boat hull has right and left steps positioned so as to optimize the boat""s trim angle at top speed, and defining right and left notches in which are pivotally mounted left and right trim tabs having forward leading edges and along oblique pivot axes causing outer corners of trailing edges of the trim tabs to move downwardly more than inner corners during downward pivoting of the trim tabs within an active hull to control boat trim angle and effectively reduce deadrise angle while maintaining a running surface trailing edge substantially free of discontinuities in the vertical direction.
U.S. Pat. No. 3,568,617, which issued to Yost on Mar. 9, 1971, describes a step-ramp V-hull. The boat construction is provided with longitudinally extending bottom surfaces including a forward section extending horizontally forward from generally amidships and curving forwardly and upwardly at its forward end, a generally horizontally disposed rear section spaced rearwardly of the forward section and above a horizontal plane containing the rearmost portions of the forward section, and an intermediate section inclined rearwardly and upwardly and extending between the rear and front ends of the front and rear sections, respectively, a step of low vertical height joining the front and rear ends of the intermediate and forward sections.
U.S. Pat. No. 5,967,078, which issued to Eilert on Oct. 19, 1999, discloses detachable wear strips for the hull of a watercraft. The watercraft having at least one removable protective wear strip is described. The watercraft hull includes at least one mounting groove extending along the longitudinal length of the watercraft hull along the lowermost portion of the hull. A wear strip is removably attached to each mounting groove such that when the watercraft hull is pulled from the water, the wear strips contact the shore to prevent damage to the watercraft hull. A series of attachment devices is embedded in the watercraft hull along the mounting groove. A series of connectors passes through the wear strip to removably attach the wear strip to the mounting groove contained in the watercraft hull. When the wear strip becomes worn, the wear strip can be removed from the watercraft hull and replaced with a new wear strip.
U.S. Pat. No. 5,390,624, which issued to Barnes on Feb. 21, 1995, discloses a boat with a pad bottom hull. A planing boat having a stern and is bow includes a hull having a generally flat central bottom surface forming a portion of a pad with the surface tapering from a specified width at the stem towards the bow. Reverse wedge surfaces blended with the central bottom surface at the stem and deadrise surfaces blended with the central bottom surface and intersecting with the reverse wedge surfaces continue forward towards the bow. The rear portion of the flat bottom surface is tipped upwardly towards the stem.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
As a boat with a planing hull achieves an adequate velocity, the forces on the boat reach an equilibrium condition in which the hull is planing with a minimal wetted surface. When a boat with an outboard motor or a stemdrive system accelerate from a standing position to wide open throttle (WOT), the angle and position of the propeller normally create a moment about the center of gravity of the boat which tends to raise the bow and facilitate the movement of the boat up to a planing position. However, when the boat has a pump jet propulsion system, the nozzle of the pump jet is typically positioned at a location which results in a thrust vector exerted on the boat at a position above the wetted contact surface between the hull and the water. This position of the nozzle creates a moment about the wetted surface of the boat which tends to cause the bow of the boat to move downward. This action is disadvantageous as the boat moves from a standing position to planing speed. In some applications, the use of ajet pump propulsion system in conjunction with a planing boat makes it extremely difficult to cause the boat to reach planing speed with a minimally wetted hull surface.
It would therefore be significantly beneficial if a boat hull could be provided which facilitates the boat""s reaching planing speed and achieving a planing position with a minimally wetted hull surface. It would be particularly beneficial if the hull can also facilitate the handling of the boat.
A boat, made according to a preferred embodiment of the present invention, comprises a hull having a port surface and a starboard surface. The port and starboard surfaces are generally symmetrical with each other and disposed on opposite sides of a central vertical plane which extends from a bow of the boat to a transom of the boat. A first channel is formed in the port surface. The first channel has a first generally planar surface and a sidewall which is contiguous with the first generally planar surface. A forward edge of the generally planar surface intersects the hull at an angle to define a continuous surface with a first portion of the hull which is forward of the generally planar surface. A rearward edge of the planar surface intersects the transom. A second channel is formed in the starboard surface. The second surface has a second generally planar surface and a sidewall which is contiguous with the second generally planar surface. A forward edge of the second generally planar surface intersects the hull at an angle to define a continuous surface with a second portion of the hull which is forward of the second generally planar surface. A rearward edge of the planar surface intersects the transom. The sidewall which is contiguous with the first generally planar surface is generally parallel to the central vertical plane. The sidewall which is contiguous with the second generally planar surface is generally parallel to the central vertical plane.
In a particularly preferred embodiment of the present invention, the first channel has a first pair of sidewalls and the second channel has a second pair of sidewalls. A first sidewall is disposed on a port side of the first channel and a second sidewall is disposed on a starboard side of the first channel. A third sidewall is disposed on a port side of the second channel and a fourth sidewall is disposed on a starboard side of the second channel. The first pair of sidewalls are parallel to each other in a preferred embodiment of the present invention. Similarly, the second pair of side walls are also parallel to each other.
A jet pump is attached to the boat and positioned to expel water in a rearward direction to exert a thrust on the boat in a forward direction. The thrust is exerted along a line which is above at least a portion of the hull.
In a preferred embodiment of the present invention, the first and second channels are displaced from the central vertical plane. The angle is within the range of 0.5 degrees to 4.0 degrees. The width of the first channel is greater than half of the distance between the central vertical plane and a port chine of the hull. The width of the second channel is greater than half of the distance between the central vertical plane and a starboard chine of the hull. The forward edge of the first channel can be disposed between the transom and a center of gravity of the boat and the forward edge of the second channel is disposed between the transom and the center of gravity of the boat. Alternatively, the center of gravity of the boat can be disposed between the forward edge of the first channel and the transom. The center of gravity can also be disposed between the forward edge of the second channel and the transom.
In a preferred embodiment of the present invention, the first and second channels are displaced from the port chine and the starboard chine of the boat, respectively. The port and starboard surfaces intersect to form the hull in a V-shape. The port and starboard surfaces intersect along a keel line which is disposed within the central vertical plane.